A failure diagnosis apparatus for diagnosing a failure occurred in a vehicle has been conventionally known (refer to PTL 1). The failure diagnosis apparatus described in the same literature is a failure diagnosis apparatus for outside a vehicle, and includes an acquisition unit, a determination standard change unit, and an extraction unit (refer to the same literature, claim 1 or the like).
The acquisition unit acquires information regarding a failure detected in a vehicle using communication. When one failure is detected in one vehicle, the determination standard change unit changes a failure occurrence determination standard for the failure to a more moderate standard in the other one or more vehicle types that are similar to the one vehicle in a vehicle state or attribute. The extraction unit extracts the vehicle state or characteristics of a vehicle surrounding environment common to the vehicle on which the failure is detected, among the other one or more vehicles, according to the more moderate failure determination standard.
It is described that by the configuration, when the failure is detected in a certain vehicle, it is possible to examine whether a sign, that a failure is likely to occur in the other vehicle in a vehicle state similar to the vehicle, is shown in the same literature. In addition, the same literature describes that according to the examination, it is possible to estimate a condition that the failure is likely to occur by searching for a common point of the vehicle state and a surrounding environment of the vehicle in which the sign is shown, and it is possible to efficiently define and repair a failed part by using the estimation result (refer to same literature, paragraph 0012 or the like).